This invention relates to tufting machines and more particularly to a tufting machine having a push rod oil seal system where the push rod exits at the head of the tufting machine.
In the production of tufted fabrics, a plurality of spaced yam carrying needles extend transversely across the machine and are reciprocated cyclically to penetrate and insert loops of yam into a backing material fed longitudinally beneath the needles. The loops are seized by loopers or hooks oscillating below the fabric in timed relationship with the needles as the loopers or hooks cross the needles just above the needle eye. In loop pile machines, the loopers point in the direction in which the backing material is being fed, hold or seize the loops while the needles are being retracted from the backing, and thereafter move away from the point of seizure to release the loops. In cut pile machines, the hooks point in a direction opposite to the direction in which the backing material is being fed so the loops are fed onto the hooks and each hook cooperates with a respective oscillating knife. Since the loops are fed toward the closed end of the hook, they cannot be released except by being cut by the respective knife. As the hooks rock away from the point of loop seizure, the knife rocks upwardly and cuts the loop. During each penetration of the backing material a row of pile is produced transversely across the backing material. Successive penetrations result in a longitudinal row of pile produced by each needle.
Tufting machines typically comprise a head to which is secured a plurality of collars connected to a sleeve. Journally disposed for reciprocation within each sleeve is a push rod. Attached to the lower end of the push rod is a needle bar carrier which in turn supports a needle bar which in turn supports a needle bar extending transversely of the machine and which carries a multiplicity of downwardly depending needles. The upper end of each push rod may be connected by a wrist pin or the like to a link which in turn may be connected by another wrist pin to a rocker arm which is in turn clamped to an oscillating main shaft so that rocking motion applied to the shaft results in reciprocation of the needle bar and thus the needles. Alternatively the main shaft may be rotated and drives an eccentric or the like connected to drive the push rods. Other driving mechanisms known in the art may also be utilized. Corresponding hooks or loopers are driven respective to the needles to receive loops of the yarn from the needles. A knife may cooperate with each respective hook for cutting the loops of yarn seized thereby.
Where the push rod reciprocates relative to the sleeve is a source of oil leaks in substantially most tufting machines. Prior art sealing systems utilize a leaded or leaded bronze bearing in conjunction with an oil seal. Prior art oil seals typically have a sharp lip which pushes oil back up into the head of the machine in an attempt to prevent the oil from leaking past the seal down the push rod onto the needle bar, and onto the backing material. Oil seals are typically made of some type of synthetic rubber or felt material, or a combination thereof. A cap is often utilized in conjunction with the oil seal. The cap may hold an oil ring to assist the oil seal in retaining the oil in the head of the tufting machine. Once an oil seal is installed, it typically cannot be adjusted.
Leakage of oil past the collar along the push rod has always been and is a continuing problem in the tufting machine art. A sliding projection, or imperfection, on the push rod shaft may result in oil leakage. Push rod travel outside the reciprocation direction may result in leakage past the push rod seal. Damage to the oil seal during installation may result in oil leakage. Excessive oil seal wear may result in leakage. Imperfections in the oil seal may result in leakage. Excessive play in push rod connections may result in leakage. Additionally, many times a prior art sealing arrangement may be replaced with a new seal arrangement only to have the push rod continue to leak past the seal.
Accordingly, the prior art has not solved successfully the problem of oil leakage past the push rod during tufting machine operation and oil seal leakage continues to plague the tufting industry. For example, in Ingram, U.S. Pat. No. 4,545,312, one proposal was made to solve the problem. Nevertheless, the problem persists.